Energy storage devices, including batteries and capacitors, are used extensively in electronic devices. In particular, capacitors are widely used for applications ranging from electrical circuitry and power delivery to voltage regulation and battery replacement. The need for on-chip power delivery is increasing with each generation of microprocessor technology. This need is increasing with the integration of on-chip voltage regulators for multicore microprocessors.
Currently capacitors are being formed using planar Metal Insulator Metal (MIM) structures embedded in the dielectric or by forming MOS capacitors in chip areas that do not have transistors using heavily doped silicon substrates. Also, another approach uses integrated trench capacitors. Another approach is making silicon capacitors using large 1.0 to 1.5 micron diameter circular openings with a 3.5 micron pitch that is patterned and dry etched in trenches using regular lithography and then filled using thermal oxide and low pressure chemical vapor deposition (LPCVD) nitride and LPCVD polysilicon for the second electrode. MOS capacitors have been previously formed in two micron deep electrochemically etched porous silicon structures with one micron mean pore diameters as well as 100 micron deep dry etched trench structures with one micron pore diameters. MIMIM structures have also been formed in one micron diameter pores.
For simplicity and clarity of illustration, the drawing figures illustrate the general manner of construction, and descriptions and details of well-known features and techniques may be omitted to avoid unnecessarily obscuring the discussion of the described embodiments of the invention. Additionally, elements in the drawing figures are not necessarily drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help improve understanding of embodiments of the present invention. The same reference numerals in different figures denote the same elements, while similar reference numerals may, but do not necessarily, denote similar elements.